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Clear out junk files and repair common Windows errorsFree Scan →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →The Seiko Prospex Alpinist SPB505J1 is the black-dial Alpinist Seiko’s UK boutique calls “Summit Black.” It pairs a 39.5 mm stainless-steel case with an automatic 6R55 movement, a rotating internal compass bezel and a manufacturer-stated power reserve of about 72 hours. Here are its specifications, price listings and the details worth checking before you buy.
What is the Seiko Prospex Alpinist SPB505?
SPB505J1 is Seiko’s black-dial model in the current Prospex Alpinist family. Its dial combines Arabic numerals with wedge-shaped indices, and LumiBrite is applied to the hands and markers. Seiko describes the design as inspired by its first sports watch, introduced in 1959; that is the manufacturer’s heritage framing, rather than an independent historical assessment. (Seiko Luxe; Seiko Official UK Online Store)
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The compass bezel is inside the crystal, not an external rotating bezel. The wearer can rotate it using the crown at 4 o’clock, then use the dial and a physical compass bearing as a directional reference. The product specifications establish the presence of the rotating compass bezel, but do not provide an independent test of its accuracy. (Seiko Luxe)
SPB505 specifications
| Specification | Seiko’s listed detail |
|---|---|
| Reference | SPB505J1 |
| Movement | Automatic 6R55, with manual winding and stop-seconds |
| Jewels | 24 |
| Power reserve | Approximately 72 hours |
| Manufacturer-stated accuracy | +25 to −15 seconds per day |
| Case diameter | 39.5 mm |
| Case thickness | 12.7 mm |
| Lug-to-lug | 46.4 mm |
| Lug spacing | 20 mm |
| Listed weight | 147 g |
| Case and bracelet | Stainless steel; case has Seiko’s super-hard coating |
| Crystal | Sapphire with inner anti-reflective coating and magnifier |
| Water resistance | 20 bar |
| Magnetic resistance | 4,800 A/m |
These are manufacturer specifications, not independent measurements. Seiko gives the movement accuracy range as +25 to −15 seconds per day; it should not be read as a timing result for a particular watch. (Seiko US; Seiko Official UK Online Store)
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
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- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
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- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
How the size and construction may affect your choice
The 39.5 mm diameter and 46.4 mm lug-to-lug measurement give a more useful starting point for estimating fit than diameter alone. Seiko lists the case thickness as 12.7 mm and the bracelet watch’s weight as 147 g. Those dimensions do not establish how it will wear on a particular wrist; if fit is decisive, try it on or compare the measurements with a watch you already wear.
The bracelet is stainless steel, and the case has a super-hard coating according to Seiko. The brand does not quantify scratch resistance in the cited product specifications, so the coating description should not be treated as a guarantee against scratches. The 20 mm lug spacing is useful when considering a strap, but does not by itself establish compatibility with a particular strap, bracelet, end link or clasp.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
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- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
What the compass bezel and ratings do—and do not—tell you
Seiko lists 20 bar water resistance and 4,800 A/m magnetic resistance. These are stated ratings, not independent test results or a specific activity recommendation. The cited product pages do not establish the watch’s suitability for a particular water sport or its performance in real-world conditions. Check Seiko’s guidance for the intended use rather than inferring more from the figures alone. (Seiko US; Seiko Official UK Online Store)
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Listed prices and regional context
On October 12, 2026, Seiko’s US product page listed the SPB505J1 at USD 995, while the official UK boutique listed it at GBP 940. These are region-specific list prices captured on that date, not verified street prices or sale prices. They should not be treated as directly comparable currency equivalents: taxes, market conditions and availability can differ by region. Check the relevant official listing for current price and stock. (Seiko US; Seiko Official UK Online Store)
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Rank #4
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- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
What to check before buying
- Confirm the reference is SPB505J1 and that the listing is for the black-dial model.
- Compare the 46.4 mm lug-to-lug and 39.5 mm case diameter with watches that fit you well; published dimensions cannot predict individual comfort.
- Verify the seller, regional warranty terms, current price and stock directly with the retailer. Seiko’s specifications do not establish third-party seller authorization or availability.
- If you plan to change the bracelet, check model-specific fit; the 20 mm lug spacing alone does not guarantee accessory compatibility.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
